There are an estimated 5-7 million long-distance caregivers (LDCs) in the United States, but little is known about this growing population. This study reviewed the literature on LDCs and examined 16 identified studies. Although studies defined LDCs differently, a composite description of who LDCs are and what they do is presented. LDCs make substantial contributions in terms of physical, financial, and social support. Distance complicates communication about care recipients' health and care needs, as well as the types of care that can be provided. Related to this, geographic separation can exacerbate care-related stressors. Implications for future research were also identified.